This invention relates to a two-piece pneumatic tire with a removable tread belt mounted on a reinforced beaded tire carcass that is typically for use with earthmoving vehicles.
The two piece pneumatic tires of the present invention are generally designed for use on large earthmover vehicles and are subjected to high stress and loads under harsh environmental conditions such as in rock quarries, mines, foundries, and other areas where tires are subjected to puncture-producing and wear-inducing conditions.
As discussed in U.S. Pat. No. 4,351,380, certain prior art tread belt tire assemblies comprise a plurality of ground-engaging shoes spaced about the periphery of the supporting structure. The heavy loads on the shoes result in great stresses being developed that sometimes lead to premature tire failure. The U.S. Pat. No. 4,351,380 is directed to an improved track belt assembly which comprise a plurality of shoes spaced about the periphery of a load-supporting structure and secured to a reinforcing belt structure disposed on the side of the shoe opposite the ground-engaging side thereof.
The large pneumatic tires, which are typically used for earthmoving vehicles, sometimes fail due to the high stress and loads caused by the harsh environmental conditions in which they are operated. These large prior art pneumatic tires had a greater tendency to fail in the crown or shoulder area of the tire due to excessive heat build up.
In the prior art, conventional solutions to these problems include increasing the robustness, and decreasing the tire deformation under load by increasing the sidewall stiffness. To further improve tire durability, the ply turn-up portion of these tires was typically reinforced.
With the continual drive to improve earthmover performance to severe continuous service conditions requiring 20 hours and up of service per day, seven days a week, there is a continuing need to provide novel methods and tire designs for improving earthmover tire durability. The present invention is directed to an improved pneumatic tire carcass and removable tread belt assembly with which the frequency of premature tire failure is thought to be substantially reduced. The present invention is also directed to providing an improved two-piece pneumatic tire assembly, which is designed to operate at long hours without damaging heat buildup. Moreover, the present invention relates to an improved two-piece pneumatic tire wherein a removable tread belt and carcass assembly has an internal cooling capability.
A two-piece pneumatic tire assembly has a removable tread belt for installing about the outer circumference of the tire carcass. The tread belt has a tread and a belt reinforcing structure located between a pair of lateral edges. The two-piece tire assembly has a plurality of subsurface passages communicating to a lateral edge. The plurality of subsurface passages extends from a central region between the lateral edges of the tread belt of the two-piece tire assembly to a lateral edge. The plurality of subsurface passages are made of a series of grooves or holes in the tread belt. The sub passages are laterally inclined. Additionally, the pneumatic tire may have subsurface passages that are formed by a laterally inclined series of grooves or holes in the carcass.
In one embodiment of the invention, the two-piece tire assembly has a tread belt that has a radially inner portion below the belt reinforcing structure and has a radially inner surface. The radially inner surface having a plurality of circumferentially continuous grooves at ribs. The carcass of this two-piece tire also has a plurality of circumferentially continuous grooves and ribs on the outer circumference of the carcass. The grooves and ribs of the radially inner surface of the radially inner portion of the tread belt and the grooves and ribs of the carcass are aligned to interlock such that the groove in the one portion interlocks with a rib of the other portion. In this embodiment the plurality of subsurface passages traverse the ribs of the tread belt and are open to one or more of the circumferentially continuous grooves of the carcass. The carcass also has a plurality of passages traversing the ribs of the carcass and being opened to one or more of the circumferentially continuous grooves on the inner surface of the tread belt. The passages of the carcass communicate with the subsurface passages of the tread belt forming a convective cooling network from a central region of the tread belt to a lateral edge. In one embodiment of this invention, the subsurface passages of the tread belt can be aligned or intersecting with the passages of the carcass. In this embodiment the passages of the carcass are grooves.